Goebelia pachycarpa (C.A.Me) - Siberian Pachycarpa
Systematic position.Family Fabaceae Lindl., genus Goebelia Bunge ex Boiss.
Synonyms.Vexibia pachycarpa (C.A.Mey.) Yakovl., Sophora pachycarpa C.A.Mey
Biological group.Perennial weed forming rootstocks.
Morphology and biology.Plant is 30-80 cm in height with thick tap roots, penetrating deeply into the soil and producing horizontal lateral roots with length over 10 m, which lie at depth of 60 cm below ground level and give vertical shoots, forming above-ground part of the plant. Stem is usually branched from near the base, sericeous, profusely foliaceous with long, upward-directed branches, covered with small accumbent white hairs. Leaves are imparipinnately compound, sericeous from both sides, with 7-13 pairs of oval or oblong leaflets. Flowers are cream, white or slightly yellowish, aggregated in narrow terminal spicate racemes; calyx is widely bell-shaped, densely and finely pubescent, with short spreading triangular teeth, which are several times shorter than calyx tube; standard is obovoid, approximately equal to wings and keel; wings are in small transverse folds along one edge and rugous. Fruit is clavate, slightly constricted indehiscent erected pod, dark brown or blackish, with 3-6 seeds. The number of pods on one shoot is 19-31; on the whole plant - 70-95. Seeds are oval or ovoid, slightly narrowed from one end and compressed laterally, brown or sometimes darker in color, glabrous, slightly lustrous, with roundish raphe. In natural conditions G. pachycarpa has mainly vegetative reproduction. Seed reproduction is poorly developed because of firm and dense testa. The emergence of seedlings and growing of shoots in plants of second year or older start in the beginning of April, this plant flowers in May and bears fruits in June-August. Minimum temperature for seed germination is 8-12°C, optimum is 25-30°C. G. pachycarpa does not form generative organs in the first year of its life.
Distribution.Iran, Afghanistan, China. Within the former Soviet Union: Central Asia and southern part of Kazakhstan.
Ecology.G. pachycarpa mainly grows among ephemeral and sagebrush vegetation on non-saline, usually fixed loess and sandy soils; also in clay steppes and ridges. It occurs in semi-desert, piedmont plains and foothills up to medium mountain belt. This plant does not need a high level of subterranean waters. It often forms dense thickets.
Economic significance.Weed of cotton and grain crops in irrigated lands, weed of grain crops in dry-farming lands. G. pachycarpa propagates steadily under low level of agronomical control. As a ruderal plant it is common in lea lands, waste grounds, near roads, in heavy-used pastures. G.pachycarpa is a poisonous plant, the above-ground part of this plant contains alkaloid pachycarpine. Control measures: deep plowing.
Reference citations:Chikov, P.S., ed. 1983. Atlas of areas and resources of herbs of the USSR. Moscow: GUGK. 340 p. (in Russian).
Keller, B.A., ed. 1934. Weed plants of the USSR. V. 3. Leningrad: AN SSSR. 448 p. (in Russian).
Komarov, V.L., ed. 1945. Flora of the USSR. V.11. Moscow-Leningrad: AN SSSR. 432 p. (in Russian).
Nikitin, V.V. 1983. Weed plants of the USSR flora. Leningrad: Nauka. 454 p. (in Russian).
Roskov, Yu. 2005. Sophora pachycarpa. Legume Web - International Legume Database and Information Service (ILDIS), version 10.01. UK, University of Reading, School of Plant Sciences: